Blade angle setting device

ABSTRACT

Device for adjusting in the inoperative condition the angular setting of all the blades of a helical wheel of a fan, which comprises a hub rigid with one of the two rims clamping the blade roots, said rims being adapted to revolve in relation to each other and having their respective positions irreversibly interconnected through one or a plurality of screw-threaded rods extending through straps carried by said rims. The rotation of said rods is obtained by means of tools engaging a radially extending shaft and connected through a swivel joint or a worm and gear drive to said rods.

United States Patent Marcellin 1 Oct; 17,1972

[54] BLADE ANGLE SETTING DEVICE Inventor: Louis Marcellin, Lille, France Assignee: Societe Anonyme des Etablissements NEU, Lille (Nord), France July 6, 1970 Filed:

Appl. No.:

Foreign Application Priority Data Dec. 19, 1969 France ..6944292 US. Cl. ..416/208, 416/147, 416/214 Int. Cl ..F04d 29/36 Field of Search ..416/207, 208, 147, 204, 205,

References Cited UNITED STATES PATENTS 9/1895 Tuerk ..416/208 10/1931 Turnbull ..416/155 7/1940 Ruths et a1 ..416/208 X 8/1951 Dehnicke ..416/207 Primary ExaminerEverette A. Powell, Jr.

' Attorney-Stevens, Davis, Miller & Mosher ABSTRACT Device for adjusting in the inoperative condition the angular setting of all the blades of a helical wheel of a fan, which comprises a hub rigid with one of the two rims clamping'the blade roots, said rims being adapted I to revolve in relation to each other and having their respective positions irreversibly interconnected through one or a plurality of screw-threaded rods extending through straps carried by said rims.

The rotation of said rods is obtained by means of tools engaging a radially extending shaft and connected through a swivel joint or a worm and gear drive to said rods.

3 Claims, 4 Drawing Figures P'A'TENTEDum 11 I972 SHEET 3 [IF 4 v PATENTEDocI 11 I972 SHEET t (If 4 1 BLADE ANGLE SETTING DEVICE This invention relates to fan wheels of the helical type of which the blade angle is adjustable in the inoperative condition.

Known devices of this type comprise as a rule mechanical assemblies having a relatively great number of parts involving a very accurate machining and a delicate assembling, such as shafts, bearings, thrust bearing, whether of the plain or rolling-contact type, driven through cams, plates, etc. It is the essential object of the present invention to provide improvements in a device of this character as described in the French Pat. No. 1,435,444 of May 21, 1965 wherein the root of each blade has a part-spherical configuration and fits between two rims of which one portion of the inner faces consists likewise of partspherical surfaces of same radius as the preceding one, the angular movements of the blades and of the rims being positively interconnected by the fact that these components comprise teeth to constitute a bevel gear assembly. In this device the two rims disposed on either side of the blade roots are assembled by means of bolts extending through elongated holes so that before tightening these bolts, or after releasing same, it is possible to set the blades in the desired angular position, the bevel gear providing the necessary simultaneous rotation of all the blades. Tightening the bolts will subsequently prevent the two rims from moving away from each other and to shift in relation to each other when the wheel rotates.

It is the essential object of the present invention to provide a device of this character which facilitates the setting, in the inoperative condition, of the blade angle of a helical fan wheel by reducing this operation to the actuation of a single, easily accessible member.

In this device for setting in the inoperative condition the blade angle of a helical wheel comprising a hub and a pair of rims clamping the blade roots of substantially part-spherical configuration, said rootsand said rims carry bevel gear teeth causing their angular movements to be positively linked, one of said rims which clamps the roots of the blades from one side of the wheel being secured to the hub thereof, the other rim which clamps the roots from the opposite side of the wheel being mounted for free rotation about said hub but held against axial movement in relation thereto, at least one screw-threaded rod being associated with pivoting straps solid with one and the other rim respectively, said rod thus interconnecting the two rims and permitting, through a rotational movement obtained by using a suitable control tool, irreversibly adjusting the relative setting of the two rims and therefore of the wheel blades, a control shaft operatively connected to said rod being disposed along one radius of said wheel.

Other features and advantages of this invention will appear as the following description proceeds with reference to two forms of embodiment given by way of example in the attached drawing, in which:

FIG. 1 is an axial view of a wheel (without blades) equipped with the device of this invention, as seen from the control side of the devices;

FIG. 2 is a section taken along the line Il-II of FIG.

FIG. 3 illustrates in axial view a wheel comprising a modified form of embodiment of the device of this invention, and

FIG. 4 is a sectional view of the wheel of FIG. 3, the section being taken along the axisIV-IV thereof.

' Referring firstly to FIGS. 1 and 2, it willbe seen that in the device according to this invention one of the two rims l is rigid with a hub 2 to which it is secured by means of screws In; this hub constitutes the hub of the helical bladed wheel and is adapted to be secured to a drive shaft (not shown) engaging the bore 3 of hub 2 which is tapered in the example illustrated in FIG. 2, although this shape is not compulsory. The other rim 4 can revolve freely about the same hub 2 but is held against axial movement in relation thereto by engaging a member 5 which is connected to hub 2 by means 20 so that the two rims l, 4 cannot move away from each other as a consequence of the centrigugal force strongly urging the roots 6a of blades 6 against the inner faces 1b, 4b respectively of said rims.

To. obtain an irreversible operative connection between the two rims and permit nevertheless an easy angular setting of one rim in relation to the other rim, one or two straps 10 adapted to pivot about an axis parallel to the wheel axisaresecured to the free rim 4. The hub supporting the other rim or the member 5 integral with the hub 2 or the rim itself is provided with one or two similar straps 9. A screw-threated rod 7 interconnects by pairs the strap or straps 10 mounted on the free rim 4 to strap or straps 9 mounted on the hub 2 or the member 5 integral with the hub 2 or the fixed rim 1.

According to this invention, two forms of operative connection may be provided between the rod or rods and the straps (1) As illustrated in FIGS. 1 and 2, the device is asymmetric and comprises only two straps. The rod 7 comprises a single thread 8 engaging a corresponding tapped portion of one of the two straps, e.g. strap 9. The end of rod 7 is plain and revolves freely in the other strap 10 it comprises shoulders 11, 12 preventing any axial movement of the strap along this rod. The rotation of the screw-threaded rod 7 is obtained by rotating a plain rod 13 extending along aradius of the bladed wheel and revolving in a plain bearing 14 carried by the free rim 4 the rotation of this rod 13 is at tended by that of the screw-threaded rod 7 through the medium of a device permitting a certain angular discrepancy, such as a double swivel joint 15.

(2) The device is symmetrical as shown in FIGS. 3 and 4. It comprises four straps, i.e. two diametrically opposite straps 16, 17 on the free rim 4 and two diametrically opposite straps 18, 19 on the member 5 attached to fixed rim 1. There are two rods 20, 21 each provided with two screw-threaded portions of opposite directions, engaging corresponding female threads formed in the straps l6, l8 and 17, 19. Each rod carries a pinion 22, 23 respectively, each pinion meshing with a tangent worm25, 26 these worms are secured to a common shaft 27 disposed along one diameter of the helical wheel. A pair of cases 28, 29 preventing the two pinion-supporting rods 20, 21 from moving away from said common shaft 27 carry the tangent worms 25, 26. As the rods 20, 21 are rotated, the straps 16, 18 and rod 20 and 17, 19 on rod 21 move away from or towards each other, at the same time revolving on opposite sides with the rim 4 and with the member 5 connected to rim 1 through the hub 2, thus obliging the rods 20,

21 to move radially from or towards each other. The length of worms 25, 26 tangent to pinions 22, 23 is sufficient to ensure a constant meshing engagement therewith, and the length of cases 28, 29 is also sufficient to permit their movement in relation to said worms.

The ends of the diametral shaft 27, as in the preceding case, are either slotted or formed with a hexagonal portion to permit the use of a corresponding tool for turning this shaft for obtaining the desired angular blade setting.

It will be readily understood that in the two forms of embodiment described hereinabove when the control rod (13 or 27) is rotated by means of a tool, the straps 9, or 16 to 19 are caused to move in relation to each other, obliging the two rims 1, 4 to revolve in relation to each other, thus producing a change in the angular setting of all the'blades 6 through the medium of the bevel gears, whose teeth are integral with the blade roots 6a and the rims l and 4.

Under these conditions it is clear that the fan wheels constructed according to the teachings of this invention can be used in turbo-machines of which it is desired to vary without difficulty the pattern of the characteristic output/pressure and output/power curves, for a given velocity of rotation, during a very short stopping of he machine, without having to remove or disassemble any part. This device is obviously applicable to a great number of industrial machines, since it affords an optimum setting of the air and gas outputs, according to requirements. More particularly, it permits replacing variable-speed driving mechanisms or systems. It is also useful in that it avoids the use of pulley-and-belt transmissions frequently used by those disregarding the magnitude of the exact loss of pressure produced in the circuit until the latter has been duly tested, wherein a speed adjustment is permissible by changing the pulley diameters now the blade pitch setting in the inoperative condition of the fan, as contemplated by the present invention, is considerably less'expensive and more rapid than the use of this conventional driving system frequently attended by an additional loss of pressure and constituting a source of wear and noise.

Although the present invention has been described and illustrated with reference to particular forms of embodiments thereof, it will readily occur to those conversant with the art that various modifications and changes may be brought thereto without departing from the basic principles of the invention as set forth in the appended claims.

What is claimed as new is:

l. A fan wheel including a device for adjusting the angular setting of all of the blades of the fan wheel while said fan wheel is not rotating comprising: a hub, a pair of rims with inner part-spherical surfaces which clamp the roots of the fan blades, fan blades having roots which have a part-spherical configuration of the same radius as the part-spherical surfaces of the rims, said roots and said rims being provided with beveled gear teeth for operatively linking the angular movement of the fan blade roots, one of said rims rigidly attached to said hub and the other said rim adapted to revolve about said hub without moving axially with respect to said hub, and an adjusting device comprising at least one pair of, pivotin straps one strap of each pair of said straps respective y connected to each of the two rims, at least one screw-threaded rod, associated with each pair of said pivoting straps, said rod adapted to operatively connect said rims, a control rod connected to said screw-threaded rod, said control rod extending in a direction radially from the shaft of said fan wheel, and means for rotating said rods thereby adjusting the relative angular relationship of said rims and revolving the beveled gear teeth, thereby changing the angular setting of said blades.

2. A device according to claim 1, wherein a double swivel joint is provided between said screw-threaded rod and said control rod.

3. The fan wheel device according to claim 1, wherein said control rod extends substantially diametrically across the hub of the fan wheel, and said device comprises: a pair of parallel screw-threaded rods, each of which carries a worm gear and has two screw threaded portions of opposite pitch thereon; and two pairs of pivoting straps, one strap from each pair attached to one of the pair of rims clamping the roots of the clades, said pivoting straps tapped and each pair of strips engaged by screw-threads to the threaded portions of one of said parallel rods; and toothed pinions on said control rod in constant meshing engagement with said worm gears, thereby operatively connecting said control rod and said parallel rods. 

1. A fan wheel including a device for adjusting the angular setting of all of the blades of the fan wheel while said fan wheel is not rotating comprising: a hub, a pair of rims with inner part-spherical surfaces which clamp the roots of the fan blades, fan blades having roots which have a part-spherical configuration of the same radius as the part-spherical surfaces of the rims, said roots and said rims being provided with beveled gear teeth for operatively linking the angular movement of the fan blade roots, one of said rims rigidly attached to said hub and the other said rim adapted to revolve about said hub without moving axially with respect to said hub, and an adjusting device comprising at least one pair of pivoting straps one strap of each pair of said straps respectively connected to each of the two rims, at least one screw-threaded rod associated with each pair of said pivoting straps, said rod adapted to operatively connect said rims, a control rod connected to said screw-threaded rod, said control rod extending in a direction radially from the shaft of said fan wheel, and means for rotating said rods thereby adjusting the relative angular relationship of said rims and revolving the beveled gear teeth, thereby changing the angular setting of said blades.
 2. A device according to claim 1, wherein a double swivel joint is pRovided between said screw-threaded rod and said control rod.
 3. The fan wheel device according to claim 1, wherein said control rod extends substantially diametrically across the hub of the fan wheel, and said device comprises: a pair of parallel screw-threaded rods, each of which carries a worm gear and has two screw-threaded portions of opposite pitch thereon; and two pairs of pivoting straps, one strap from each pair attached to one of the pair of rims clamping the roots of the clades, said pivoting straps tapped and each pair of strips engaged by screw-threads to the threaded portions of one of said parallel rods; and toothed pinions on said control rod in constant meshing engagement with said worm gears, thereby operatively connecting said control rod and said parallel rods. 